The purpose of this proposal is to request funds to support the travel and subsistencies for participants at the International Symposium on "Peroxisomes: Biology and Role in Toxicology and Disease" which will be held June 28-July 2, 1995 at the Aspen Institute, Aspen, Colorado. This International Symposium will serve as a forum to celebrate the thirtieth anniversary of the introduction in 1965 of the "peroxisome" concept by Christian de Duve, and to discuss the recent advances related to mechanisms by which peroxisomes and peroxisome proliferators play a role in disease and toxicologic and carcinogenic processes. We have invited a total of 48 participants from 12 countries: Canada (I); France (2); Germany (3); Japan (7); Switzerland (1); United Kingdom (5); United States of America (21); Belgium (2); The Netherlands (3); Chile (1); Finland (1); and Sweden (1). All participants have been selected based on their leadership role, and their published records in the field of peroxisome biology, cellular and molecular mechanisms of peroxisome proliferator-induced pleiotropic responses, molecular basis of peroxisomal diseases, and the impact of peroxisome proliferators on human health. The themes to be developed include: 1) peroxisome biogenesis in higher and lower eukaryotes; 2) metabolic functions of peroxisomes; 3) peroxisome proliferators activated receptor (PPAR) mediated pleiotropic responses; 4) peroxisome proliferators: pleiotropic responses (continued); 5) peroxisome proliferators: carcinogenicity and implications; and 6) peroxisomal genetic disorders. The key participants have been selected based on their leadership role, originality of their contributions, and their published records. In addition, careful attention has been given to include younger highly promising researchers early in their careers who have initiated independent research programs. We also sought input from various individuals, organizations and regulatory agencies for possible participants and relevant topics for discussion. The fundamental criteria for selecting participants included the stature and originality of their scientific contributions, and in the case of researchers early in their careers, the potential for independence and the originality of their current research. It is of great significance to note that Professor Christian de Duve, Nobel Laureate, has graciously agreed to deliver a special lecture entitled "The Peroxisome in Retrospect". Drs. N. Edward Tolbert and Harry Beevers, who are members of the U.S. National Academy of Sciences and who made seminal contributions to our knowledge of peroxisomes/glyoxisomes, have agreed to chair sessions. Ron Evans, another member of the U.S. National Academy of Sciences, has also agreed to speak at this symposium on the role of PPAR and RXRalpha in transcriptional activation of genes. The presence of these stalwarts will add considerable lustre and intellectual electricity to this meeting. This mix of the active researchers-established leaders and those early in their careers will provide a dynamic forum for intellectual interplay. This symposium will bring together leading scientists from an international fraternity. We anticipate that this meeting will foster interdisciplinary and international collaborations. Poster presentations are included for informal exchange of information and ideas. A session dedicated to the discussion of selected posters, including the winning entries in a young scientist competition, will be added. A special session on the development of transgenic and knock-out animals related to peroxisomal genes will be added as these studies emerge from now until the time of the symposium in June 1995.